Telephone system



Aug. 24, 1937.

T. F. CROQKER TELEPHONE SYSTEM FiledJune 24, 1935 F Wm WC F m M O m M W s A 3 i Mun w 4 =0 J7 wuwEo .x vfldmmm Elm EEzmu l 9.23 n u wxz 128% 228% A TTORNEY.

Patented Aug. 24, 1937 UN-iT D STATES PATENT OFF-ICE TELEPHONE SYSTEM Delaware Application June 24, 1935, Serial No. 28,069

Claims.

The present invention relates in general to telephone systems, and the object of the invention is to provide novel and efficient secretarial answering equipment for use in such systems.

b By means of this equipment an operator at the central office can perform the duties of a scoretary for a considerable number of subscribers to the extent of answering their telephones when they are absent and taking messages, making 1 appointments, etc. The invention may be considered as an improvement on the answering sys tem disclosed in BurgenerPatent No. 1,922,879, and Kahn Patent No. LQSJAQB.

A special feature of the present invention is a 1-- centralized answering system, in which an operator may not only answer calls for subscribers in her own ofiice but may answer calls for subscribers in one or more outlying ofiices.

The invention and various features thereof including the above will be described hereinafter with reference to the accompanying drawing, which shows in diagrammatic form the circuits and apparatus involved in the invention and sufiicient of the telephone exchange equipment to enable the invention to be clearly understood.

Referring to the drawing, the equipment shown to the right of the dotted line is in the main office, or ofiice where the answering operator is located, while the equipment shown to the left of 30 the dotted line is located at a distant or outlying ofiice. These offices may be part ofthe same network, and there may, of course, be several other outlying offices in addition to the one shown.

35 The reference character A indicates the telephone of a person in the area covered by the outlying office, who has subscribed to the answering service. This telephone has two lines. There is a regular service line comprising conductors 40 2 and 3 which extends to the exchange, and assuming it is an automatic exchange, terminates there in the usual line switch and connector banks as indicatedin the drawing. There is also an answering service line comprising conductors 45 4 and 5. This line is normally disconnected, but

may be connected up by means of a key K whenever the subscriber at A leaves the premises.

At the outlying office or exchange there is a finder switch F, which has access to all the 50 answering lines such as the line 45. The finder F may be a single motion rotary switch of the well known construction. Associated with the 1 finder F is a trunk line comprising conductors I 5 and I5 and extending to the central office where 55 the answering operator is located.

Certain subscribers in the area served by the central office may also have the answering service, and one such is the subscriber having the telephone B. This telephone: may have the same line arrangement as telephone A or may have 5 the somewhat different arrangement shown. As shown, thereis a single line extending from telephone B to the exchange, terminating there in a line switch and connector banks. There is also provided an answering line local to the exchange, 1 which may be connected up by means of a key K With this arrangement the subscriber at B will telephone in to the exchange whenever he leaves his oflice and request that his answering line be connected up.

The answering lines at the central office and also the trunk lines incoming from outlying offices are accessible to finder switches such as the finder F Associated with each finder there is a trunk line extending to the answering opera- 20 tors position. Thus the trunk line 42-43 extends from the finder F to the operators position where it terminates in a listening key K and a hold key K The operators headset is indicated at O, and may be connected across any trunk by operating the. associated key such as K It will be assumed now that the subscriber at A leaves his telephone unattended and operates the key K before leavingso as to obtain the answering service while away. If he has any special instructions to leave with the answering operator as regards calls received in his absence he will, of course, cal-1 the operator and tell her what to do.

When a call comes in the bell at station A will ring and also, since key K is now in operated position, a portion of the ringing current will return to the exchange via the answering line 45 and, will operate the ring-up relay 6. Relay 6, upon energizing, locks itself in a circuit which includes the finder start relay I l. The latter relay, upon energizing, connects battery to the upper winding of the electro-polarizedtest relay 9, and also connects ground to the lower or polarizing winding of this relay. Relay 9 does not operate due to current in its polarizing winding alone There is also a branch circuit over which the stepping magnet I0 is connected in parallel with the lower winding of relay 9, and accordingly the magnet begins to operate, advancing 5 the wipers l2l4 in search of the answering line on which the call has been received.

When the finder test wiper l4 reaches the i test contact of the line in question, on which a ground has been placed by relay 6, a circuit is completed for the upper winding of the test relay 3, and this relay energizes, stopping the movement of the finder by opening the circuit of magnet ID. The finder wipers l2 and I3 will now be resting on the contacts in which the line 4-5 is terminated. Relay 9 also connects up the trunk comprising conductors l5 and I6.

At the central oflice there is a high resistance relay 33 bridged across the trunk and this relay now pulls up. Relay 8, however, does not operate at this time, due to the high resistance of relay 30. Upon energizing, relay 38 connects ground to the finder start lead 44, and connects battery to the cut-01f relay 3 I, the latter operation serving to mark the trunk line in the test bank of the finder F The grounding of start lead 44 results in the energization of start relay 40. Relay 40, on energizing, connects ground to the upper winding of test relay 33, and closes parallel circuits for the polarizing winding of this relay and for the stepping magnet 4|. Magnet 4| accordingly begins to operate and advances the finder in search of the trunk line |5|6.

When the trunk line is found, the test relay 39 energizes in series with the cut-off relay 3|, stopping the finder by opening the circuit of the stepping magnet 4|. The cut-off relay 3| operates at the same time and disconnects relay 30 from in bridge of the trunk line. Relay 3| also connects battery to its own winding to provide against the falling back of relay 36.

In addition to stopping the finder the test relay 39 closes a locking circuit for its lower winding, and places ground on the test wiper 36. This latter operation serves to maintain the cut-off relay 3| and also makes the trunk line |5--|6 busy to other finders. Relay 33 also breaks the start lead 44 extending to start relay t0 and prepares an extension of the start lead which continues to the next finder via 45 as soon as relay 40 falls back. Finally relay 39 closes a circuit for the lamp L, which lights up and notifies the operator that a call has been received on the associated trunk line.

When the operator observes the lighted lamp she will answer the call by throwing the key K which bridges her headset 0 across the trunk line 42-43. At the same time a circuit is closed for relay 33. Upon energizing, relay 38 connects start lead 54 to the extension 45 at a new point to provide against the falling back of relay 39, grounds the test wiper 36 for a similar reason, and breaks the locking circuit of relay 39. The latter relay therefore falls back and puts out the lamp L.

The bridging of the operators headset across the trunk line results in the energization of relay 8 at the distant office. On energizing, relay 8 closes a new circuit for relay 9, opens th circuit of start relay thereby unlocking relay 6, and'bridges the impedance coil 1 across the line wipers I2 and I3 of the finder F. This latter operation simulates the removal of the receiver at the telephone A and has the effect of stopping the ringing and completing the talking circuit in the automatic exchange in the well known manner. The operator is therefore placed in communication with the calling party.

To facilitate the work of the operator she may be provided with a bank of lamps such as L, there being one of these lamps for each local answering line and for each trunk line accessible to the finders F When the key K is operated, one of these lamps will light up. If the lighted lamp is one associated With a local answering line, such as the answering line provided for telephone B, the operator will be advised of the precise telephone number called. If the lamp lighted is a trunk lamp, however, as in the case being considered, the operator is not advised as to the telephone number, but is notified as to the particular outlying exchange in which the called telephone is located.

The operator is also provided with a hold key K for each trunk line. When the key K is operated it closes a new circuit for relay 38, and places a bridge across the trunk line to maintain the call in answered condition. On a trunk call from an outlying office this bridge will hold up relay 8. The hold key is useful in that it permits the operator to restore the listening key K and operate a similar key to answer a call on another trunk, which she may find it advisable to do if unable to promptly dispose of the call on the trunk associated with key K Assuming now that the call is satisfactorily taken care of, the calling party will hang up, releasing his connection with the line of telephone A in the usual manner and the operator will restore her listening key K When the key is restored relay 8 in the distant ofiice falls back, breaking the holding circuit of relay 9, and again closing the start circuit extending to relay The finder F is thus made ready to handle another call. At the central oflice the restoration of the key K causes the deenergization of relay 38. On falling back relay 38 restores the start circuit to normal and takes ground off the test wiper 36. The latter operation permits cut-off relay 3| to restore and connect relay 30 in the bridge of the trunk again. Thus all the equipment concerned is restored to normal condition.

In view of the explanation already made, the operations involved in answering a call intended for a telephone such as B will be readily understood. If telephone B is called when the subscriber is absent, the key K will have been operated, and relay 32 will therefore ring up and lock, placing ground on the start lead 44 through its locking winding. This will start up a finder such as F by means of a start relay such as 40. When the finder reaches the line on which the call is present it stops as previously described and a circuit is closed for the cut-off relay 33. Relay 33, on energizing, connects battery to its own winding, and unlocks relay 32, which deenergizes. The remaining operations are similar to those described in connection with the previous call.

It will be noticed that the start lead 44 is permanently connected to battery through a resistance 46. This resistance is high enough to prevent interference with the operation of start relays such as 40 and is low enough to provide for holding up relays such as 32 when the start circuit is temporarily opened upon transfer from one finder to the next. The utility of this resist.- ance path to battery will be evident if two simultaneous calls are considered. Two relays such as 32 will be locked up and a finder will be started. When one of the lines is found the start circuit is transferred to the next finder, being opened momentarily, however, during the time required for the relay such as 40 in the operated finder to fall back. The opening of the start circuit cannot unlock the relay 32 of the line not yet found because of the permanent connection to battery through resistance 46.

The invention having been described, that which is believed to be new and for which the protection of Letters Patent is desired will be pointed out in the appended claims.

What is claimed is:

1. In an answering system, a subscribers telephone, two separate and independent lines extending from said telephone to an exchange, one of said lines being the usual line for incoming and outgoing service and the other line being an answering line, means at the telephone station for connecting said lines together at the station, whereby an incoming call to said telephone may be routed from the telephone back to the exchange over the answering line, and means including an automatic switch responsive to such call for extending the answering line to an operators position.

2. In an answering system, a subscribers telephone, two separate and independent lines extending from said telephone to an exchange, one of said lines being the usual line for incoming and outgoing service and the other line being an answering line, means at the telephone station for connecting said lines together at the station, whereby an incoming call to said telephone may be routed from the telephone back to the exswering line to answer the call.

3. In an answering system, two exchanges, answering lines in one exchange, means for connecting said lines with subscribers telephone lines to receive calls, an inter-exchange trunk line, means in said one exchange for connecting an answering line on which a call is received to said trunk line, said means comprising an automatic switching device responsive to the call, an operators position in the other exchange, an automatic switching device in the other exchange controlled over said trunk, and means including said last mentioned switching device for extending said trunk line to the operators position to enable the operator to answer the call.

4. In an answering system, a main exchange,

answering lines terminating in said exchange,

means for connecting said lines to subscribers lines to receive calls, an operators position, means including a call responsive switching device for extending any answering line on which a call is received to said position, a second exchange having answering lines, a trunk line connecting said exchanges, means in said second exchange for connecting an answering line on which a call is received to said trunk line, and means in the main exchange including said switching device for extending said trunk line to the operators position.

5. In an answering system, two exchanges, answering lines in each exchange, means for connecting said lines to subscribers telephone lines to receive calls, an operators position in the first exchange, means including switching mechanism for extending any answering line in the first exchange to said position, and means including said switching mechanism and an inter-exchange trunk line for extending any answering line in the second exchange to said position.

6. In an answering system, an operators trunk line having a finder connected thereto, answering lines and a trunk line accessible to said finder, another finder connected with said trunk line, answering lines accessible to said second finder, and means including said finders for connecting the operators trunk to any answering line.

'7. In a finder system, a finder, a line accessible thereto, a ring-up relay bridged across said line, a start relay for said finder, and a start circuit for said finder including a locking winding on said ring-up relay and said start relay.

8. In a finder system, a plurality of finders, a start circuit normally extending to a start relay in the first finder, means for transferring said circuit to the start relay in the second finder when the first finder is in use, lines accessible to said finders, ring-up relays bridged across said lines, locking windings on said ring-up relays adapted to be conneccted to said start circuit when the relays are energized to start a finder, and a permanently connected branch of the start circuit adapted to prevent unlocking of ring-up relays during the transfer of the start circuit.

9. In a finder system, a trunk line terminating in a finder, lines accessible to said finder, means responsive to ringing current on one of said lines for starting said finder, and means in the trunk for maintaining the operated condition of the finder after the line is found independent of current flow over the line.

10. In a telephone system, a line, a finder having access to said line, means controlled over said line for starting said finder and causing it to find said line, other finders, and means independent of current flow over said line for making the line busy to said other finders.

THOMAS F. CROCKER. 

